Didn't realise that the 916 series only had 220 discs, but that kind of proves that it would be enough braking power when working properly.
I was formally taught not to use the rear brake in an emergency stop situation, since it will be in the air if you're doing it right anyway, the still rotating rear wheel will act as a stabilising gyro to help you come back down in a straight line.
So I reckon it would be good enough for general and trail braking when you really don't want to temp a lock up.
I think that wavy discs are a bit lighter than normal round ones sometimes, but not always.
Preferably you would buy one that stated the weight to make sure.
For what it's worth I think Yamaha discs are compatible with Ducati for more scope.
Obviously Ti disc bolts will help with a few grams.
Not sure if there is enough room to make an alloy disc carrier worth the trouble?
I'm assuming you're already using an alloy sprocket?
Ultimately you will make more difference with a lighter wheel.
There were two versions of the Brembo three spoke wheel.
The early one had thicker spokes at the periphery. Later ones are thin at the periphery and thick at the base and are a bit lighter.
I think the much later Marchensi 5 spokes are lighter still, but not sure about interchangeability?
